Secondary batteries are in widespread use for powering electronic devices such as cell-phones and IT devices, not to mention replacing primary batteries. Especially, because nonaqueous electrolyte secondary batteries represented by lithium ion batteries have high energy density, application of them to industrial large electric devices such as electric cars is facilitated.
FIG. 13 is an exploded perspective view of a prior-art nonaqueous electrolyte secondary battery (see Patent Document 1, for example).
As shown in FIG. 13, the nonaqueous electrolyte secondary battery 100 has a structure in which a power generating element 11 is housed in a metallic container main body 10 having an opening 10x and the opening 10x is closed with a lid portion 20 and sealed by laser welding or the like.
The power generating element 11 has a structure in which a positive electrode and a negative electrode which are band-shaped electrodes are wound into an elongated circular cylindrical shape with separators interposed therebetween. In a wound state, the positive electrode and the negative electrode are displaced from each other in different directions of opposite ends of a winding axis and their end portions are respectively positioned at opposite ends of the power generating element 11. Furthermore, the end portions of the respective electrodes do not support active material and pieces of metal foil which are substrates are exposed at the end portions. To the pieces of metal foil 11a, 11a′ protruding from the opposite end portions of the power generating element 11, a current collection connecting body 12 on a positive electrode side and a current collection connecting body 12′ on a negative electrode side which are conductive metal plates are respectively connected.
One end of the current collection connecting body 12 extends parallel to a surface of the power generating element 11 and a through hole 12a is formed in a surface of the one end. The other end is bent toward a side face of the power generating element 11 and pinched by a pinching plate 14 together with the wound piece of metal foil 11a, which is exposed on the side face of the power generating element 11, and connected and fixed by ultrasonic welding or the like. The current collection connecting body 12′ on the negative electrode side has a similar structure.
At opposite ends of the lid portion 20, through holes for pulling out terminals are formed. In FIG. 13, only the through hole 20a on the positive electrode side is shown and a through hole on the negative electrode side is hidden under a part described later and is not shown. An insulating sealing member 13 is positioned between the lid portion 20 and the current collection connecting body 12 of the power generating element 11. The insulating sealing member 13 is a member made of synthetic resin and having an insulation property and certain elasticity and a through hole 13a concentric with the through hole 20a of the lid portion 20 and the through hole 12a of the current collection connecting body 12 is formed in a surface of the insulating sealing member 13.
Furthermore, an insulating sealing member 21 is positioned to be superimposed on a portion of the lid portion 20 near a short-side end portion thereof. The insulating sealing member 21 is a member made of synthetic resin similar to the insulating sealing member 13. A through hole 21b concentric with the through hole 20a of the lid portion 20 is formed in a surface of the insulating sealing member 21. A cylindrical portion 21c is formed on a side of the insulating sealing member 21 facing the lid portion 20 and the through hole 21b extends through the cylindrical portion 21c. The cylindrical portion 21c has an outer shape conforming to the through holes 20a and 13a and is fitted into the respective through holes.
Moreover, a recessed portion 21a is formed on a principal face of the insulating sealing member 21. A connecting member 32 is disposed to be fitted into the recessed portion 21a and a fixing member 31 is disposed to pass through the through hole 21b. A terminal member 30 is disposed to cover these respective members. The terminal member 30 is a plate-shaped member made of conductive metal such as aluminum, an aluminum alloy, and the like and provided with a through hole 30b concentric with the through hole 21b of the terminal member 30 and a through hole 30a through which the connecting member 32 passes.
The fixing member 31 is a member made of conductive metal such as aluminum, copper, and an alloy of them and for electrically connecting the terminal member 30 and the current collection connecting body 12 of the power generating element 11 and mechanically coupling the lid portion 20 and the power generating element 11.
The connecting member 32 is a member made of highly conductive metal such as iron and steel such as stainless steel and chromium molybdenum steel with high strength and for electrically connecting the nonaqueous electrolyte secondary battery 100 to an external load. The connecting member 32 is formed by a bolt portion 32a having a threaded surface and an anti-rotation portion 32b provided at one end of the bolt portion 32a. The anti-rotation portion 32b is in a shape conforming to the recessed portion 21a of the insulating sealing member 21 and is fitted into the recessed portion 21a to thereby restrict rotation of the bolt portion 32a about a rotation axis and prevent the connecting member 32 from running around.
Next, with reference to FIGS. 14(a) and 14(b), a structure of the prior-art nonaqueous electrolyte secondary battery 100 around an electrode portion 23 will be described. Here, the electrode portion 23 refers to an element formed by the terminal member 30, the fixing member 31, and the connecting member 32. FIG. 14(a) is a plan view of a portion of the nonaqueous electrolyte secondary battery 100 and FIG. 14(b) is a sectional view of a portion taken along straight line A-A in FIG. 14(a).
As shown in FIG. 14(a), the fixing member 31 and the bolt portion 32a of the connecting member 32 of the electrode portion 23 are disposed on a straight line parallel to long sides of the lid portion 20.
As shown in FIG. 14(b), the cylindrical portion 21c of the insulating sealing member 21 passes through the through hole 20a of the lid portion 20 and the through hole 13a of the insulating sealing member 13 and an end face of the cylindrical portion 21c is in contact with a principal face of the current collection connecting body 12, with which a principal face of the insulating sealing member 13 is also in contact. The fixing member 31 passes through the through hole 30b of the terminal member 30, the through hole 21b of the insulating sealing member 21, and the through hole 12a of the current collection connecting body 12. One end exposed on the lid portion 20 and the other end exposed on a side of the current collection connecting body 12 of the fixing member are riveted and shaped into rivet ends 31a and 31b. 
Because the respective rivet ends 31a and 31b have larger outer diameters than the respective through holes, the terminal member 30, the insulating sealing member 21, the lid portion 20, the insulating sealing member 13, and the current collection connecting body 12 are pressure-bonded to each other and fixed integrally by being pinched between the rivet ends 31a and 31b. The current collection connecting body 12 and the terminal member 30 are electrically connected to each other by being connected by the fixing member 31. Because a side face of the fixing member 31 is covered with the cylindrical portion 21c of the insulating sealing member 21, the lid portion 20 and the fixing member 31 are insulated from each other.
In this way, electric power generated in the power generating element 11 is taken out of the container main body 10 through the electrode portion 23. Specifically, a solderless terminal of a wire of an external load (not shown) is attached to the bolt portion 32a and a nut conforming to a thread on the bolt portion 32a is fastened to fix the solderless terminal to the terminal member 30 to thereby complete electric connection between the nonaqueous electrolyte secondary battery 100 and the external load.